Sonar devices variously referred to as "fish finders" or "depth sounders" have been available for some time which are designed to tell a user what is below the boat. However, in general, it has only been through the use of expensive and complex "scanning" sonar that a fisherman has been able to tell where the fish are actually located below the boat and to thus answer the ages old question as to which side of the boat from which the fisherman should fish.
While devices and systems have been developed which "aim" sonar transducers in different directions so as to manually scan for fish, such devices are cumbersome and inconvenient for fisherman to use. It will be understood that transducers of the type being referred to here are devices which receive electrical energy from a transmitter or the like and convert this electrical energy into mechanical or acoustical energy that travels as a sound wave through the water, and which also convert back, to electrical energy, reflected sound waves received thereby whether the sound waves are reflected off of fish, the bottom or other targets. Thus, such transducers act in a manner similar to both a loudspeaker and a microphone.
In general, scanning transducers rely on mechanically rotating a transducer within a housing, or mechanically or electrically switching between a plurality of transducers and/or changing the phase relationships of the transducers, with the transducers being typically mounted in a hemispherical array. The information received from the transducers is displayed on a cathode ray tube or a similar display device and the information displayed is generally a sweeping pattern on the display which corresponds to the sweep of the transducer.